My friend has been here for 30 years from mexico how does he get his residency?

There is no simple path based upon length of time in the U.S. Eligibility for permanent residence will depend upon more detailed information about his immigration history and ties to the country. Most individuals obtain residence through family-based or employment-based immigrant visa petitions. You can read more about immigration options at http://myattorneyusa.com/immigration-to-the-usa.